public class Test {
    public static String myToString(int[] array) {
        String str = "[";
        for (int i = 0; i < array.length; i++) {
            str = str + array[i];
            if (i != array.length - 1) {
                str = str + ",";
            }
        }
        str = str + "]";
        return str;
    }

    public static void main(String[] args) {
        int[] array = {1,2,3,4};
        String ret = myToString(array);
        System.out.println(ret);
    }
}